Illuminating apparatus, image display apparatus, and projector

Abstract

An illuminating apparatus includes at least two solid light-emitting elements including a first solid light-emitting element and a second solid light-emitting element; a polarized-light combining unit that combines a first polarized light of a first oscillation direction and a second polarized light of a second oscillation direction substantially perpendicular to the second oscillating direction to guide the first polarized light and the second polarized light to an illumination direction by transmitting or reflecting the first polarized light and reflecting or transmitting the second polarized light; and a phase modulating element that converts a polarized light from the polarized-light combining unit into either of the first polarized light and the second polarized light.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present document incorporates by reference the entire contents of Japanese priority documents, 2004-67230 filed in Japan on Mar. 10, 2004, and 2004-95605 filed in Japan on Mar. 29, 2004.BACKGROUND OF THE INVENTION[0002]1) Field of the Invention[0003]The present invention relates to an illuminating apparatus, an image display apparatus, and a projector, and more particularly, to an illuminating apparatus for a projector.[0004]2) Description of the Related Art[0005]Generally, light emitting diode (LED) has an advantage of a long lifetime and a high energy-conversion-efficiency over an ultrahigh-pressure mercury vapor lamp. For this reason, the LED is gaining popularity as light source for an illuminating apparatus. However, a single LED has a smaller emission amount compared to the ultrahigh-pressure mercury vapor lamp. Because a comparatively large amount of light is required for a projector, a technology for making an array of LEDs is...

AI Technical Summary

Benefits of technology

The present invention provides an illuminating apparatus, a projector, and an image display apparatus that use solid light-emitting elements to produce light. These light-emitting elements include a polarized-light combining unit that combines two polarized lights in a way that guides them to an illumination direction. A phase modulating element converts the polarized light into either of two different directions. A rod integrator makes the light from the solid light-emitting elements uniform in intensity distribution. A color filter transmits and reflects light in different wavelength regions. A reflecting portion reflects the light from the color filter back to the solid light-emitting elements. A spatial light modulating element modulates the light from the rod integrator according to an image signal. These technical effects improve the quality and efficiency of the illuminating and projecting apparatuses.

Problems solved by technology

However, because an angle that the spatial light modulator can cover is limited, it is difficult to effectively use the light flux from the light source.

Therefore, even if an LED array is employed in a projector to increase the light intensity, it is difficult to effectively use all the light flux from the light source because the etendue is preserved.

With this type of configuration, because the white light is separated into three colors by the color filters for each of the colors, an illumination optical system grows in size, and it is difficult to obtain a bright image with an even intensity distribution.

As described above, the conventional technology has problems of supplying an illumination light with a high brightness and a high usability and obtaining a bright image with an even intensity distribution.

Images